1. Field of the Invention
The present invention relates in general to a gas concentration device and more particularly to a gas concentration device having a cooled adsorbing element.
2. Description of the Related Art
Heretofore a gas adsorption honeycomb rotor formed of a wound laminate of a corrugated thin sheet and a flat sheet, with gas adsorbents such as silica gel and/or zeolite on the surface of the laminate, has been marketed. Recently, gas concentration devices having gas adsorption rotors have been adopted for use in pollution preventing equipment, and thus, the usage is extending.
A prior gas concentration device is explained referring to FIG. 12. Honeycomb rotor element 1 consists of a flat thin sheet and a corrugated thin sheet. Honeycomb rotor 1 has particles of the gas adsorbents such as silica gel and zeolite on the surface. A geared motor 2 has reduction gears to rotate the rotor element 1 through belt 3.
Casing 4 supports above-mentioned geared motor 2, belt 3 and rotor element 1 rotatively. Moreover, seal 5 creates an airtight seal between rotor element 1 and casing 4. In addition, casing 4 is divided into an adsorbing zone 6 and a desorbing zone 7. Blower 9 blows the process air to remove gas or to dehumidify. The dust in desorption air is removed by filter 10, the air is heated by desorption air heater 11 and sent to desorbing zone 7.
The function of the prior gas concentration device will now be explained. The rotor element 1 is driven by geared motor 2 and process air blower 9 sends the process air such as the indoor air through adsorbing zone 6. The gas or moisture in the process air are adsorbed by the adsorbent particles attached to the surface of rotor element 1 in adsorbing zone 6. As the rotor element 1 rotates, the portion that adsorbed the gas or moisture moves to desorbing zone 7. Because the hot air heated by the desorption air heater 11 enters the desorbing zone 7 by force of blower 12, the portion of the rotor element 1 in desorbing zone 7 is heated by the hot air and adsorbed gas or moisture are desorbed from the portion. Thus, the gas concentration device removes the gas or moisture in the process air and discharges the gas or moisture to the desorption air. If the gas discharged in the desorption air is a harmful gas such as an organic solvent vapor, the gas is changed into a harmless gas by means of incineration etc. and is discharged into the atmosphere.
The prior gas concentration device is able to remove gas or moisture in the process air as above-mentioned. However, there is a problem that the ability to remove gas or moisture from the process air decreases with increasing process air temperature. If the process air is cooled with a conventional refrigerator having a compressor, the refrigerator consumes a lot of energy for cooling and the processing cost becomes high. In addition, there is a problem of the exhaust of carbon dioxide because there is a lot of energy consumption. There are also problems associated with using Freon as the refrigerant in the refrigerator. Further, refrigerators are expensive because of their complex structure.